AppVeyor: prevent unnecessary builds (#2888)

* prevent unnecessarybuilds

* readd qt5 string

sadly this is needed as of now:
ff6b0f86ec/cockatrice/src/releasechannel.cpp (L59-L68)

* wrap asterisks

* fixed with validator

https://ci.appveyor.com/tools/validate-yaml

* complete link

* add helpful links

this should not trigger a appveyor build

* add space in readme

this should not trigger a appveyor build

* highlight c++ types

this should not trigger a appveyor build

* remove empty line

this should not trigger a appveyor build

* declutter dockerignore

this should not trigger a appveyor build

.appveyor.yml

@@ -1,8 +1,23 @@
 version: 2.3.18-branch-{branch}-build-{build}
+
+# Skipping commits affecting specific files (GitHub only). More details here: https://www.appveyor.com/docs/appveyor-yml
+skip_commits:
+  files:
+    - .github/*
+    - .travis/*
+    - .tx/*
+    - webclient/*
+    - .*ignore
+    - .gitlab-ci.yml
+    - .travis.yml
+    - '*.md'
+    
 image: Visual Studio 2015
+
 cache:
     - c:\protobuf-release
     - c:\zlib-release
+    
 environment:
     matrix:
         - qt_ver: 5.9\msvc2015_64
@@ -17,6 +32,7 @@ environment:
           cmake_generator: Visual Studio 14 2015
           cmake_toolset: v140_xp # use the windows XP compatible toolset
           target_arch: x86
+          
 install:
     - ps: |
         if (Test-Path c:\protobuf-release) {
@@ -37,8 +53,10 @@ install:
             cmake . -G "$env:cmake_generator" -T "$env:cmake_toolset" -DCMAKE_INSTALL_PREFIX=c:/zlib-release
             msbuild INSTALL.vcxproj /p:Configuration=Release
         }
+        
 services:
     - mysql
+    
 build_script:
     - ps: |
         New-Item -ItemType directory -Path $env:APPVEYOR_BUILD_FOLDER\build
@@ -59,15 +77,17 @@ build_script:
         (New-Object PSObject | Add-Member -PassThru NoteProperty bin $new_name | Add-Member -PassThru NoteProperty cmake $cmake_name | Add-Member -PassThru NoteProperty commit $env:APPVEYOR_REPO_COMMIT) | ConvertTo-JSON | Out-File -FilePath "latest-$env:target_arch" -Encoding ASCII
         Push-AppveyorArtifact "latest-$env:target_arch"
         $version = $matches['content']
+        
 test: off
+
 deploy:
-  description: "Dev build of Cockatrice"
   provider: GitHub
   auth_token:
     secure: p+7wPVry2XEa6TBm9XH8IaQZbBmXQ/J2ldbGmcIxUZD3NkkPrSRRlmE7Of1CBBIO
+  description: "Dev build of Cockatrice"
   artifact: /.*\.exe/
   draft: false
   prerelease: true
   force_update: true
   on:
-    appveyor_repo_tag: true
+    appveyor_repo_tag: true